Thursday, 11 August 2011

Giant bird from the Cretaceous of Kazakhstan.

This month a team lead by Darren Naish of the School of the School of Earth and Environmental Sciences at the University of Portsmouth publish a paper in the journal Biology Letters in which they announce the discovery of a new giant bird from the Cretaceous of Kazakhstan. The bird has been identified from a from a fragmented lower jaw from the Late Cretaceous Bostobynskaya Formation, northeast of the Aral Sea in Kazakhstan. It was named Samrukia nessovi in honor of the Samruk, a mythical, phoenix-like Kazakh bird and Lev Nessov, a Russian vertebrate palaeontologist who did much work in Central Asia.

The lower jawbone of Samrukia nessovi.

These fragments were initially reconstructed as the jaw of an oviraptosaur-like dinosaur and found there way to the Institut royal des Sciences naturelles de Belgique in Brussels, where they were discovered in 2010 by palaeontologist Pascal Godefroit. Godefroit recognized that there was a problem with the way the jaw was reconstructed, and contacted dinosaur expert Darren Naish and Gareth Dyke, an expert on fossil birds from University College Dublin. Together they were able to determine that the oviraptosaur reconstruction was wrong; the only parts of the specimen that were diagnostic of an oviraptosaur type dinosaur were plaster additions, which did not match well with the actual fossil, once these were removed a proper analysis of the fossil could be made, confirming Godefroit's suspicion that this was in fact the jaw of a large bird.

The oviraptosaur reconstruction of the jawbone.

Birds are reasonably well known from the Cretaceous, but most specimens are small, chicken sized or less, whereas this was a much larger creature, with a lower jaw at least 30 cm in length. It is not possible to reconstruct a whole bird from a lower jawbone, but comparison with modern birds suggests a man-sized flightless bird or a flying bird with a wing-span of at least 4 m.
Two possible reconstructions of Samrukia, with a human and a more typical Cretaceous bird for comparison. By dinosaur artist John Conway.

There has been one other giant bird described from the Late Cretaceous; Gargantuavis philoinos, a large, flightless bird from southern France, was described in a paper in the journal Nature in 1995 by a team lead by Eric Buffetaut of the Laboratoire de Géologie de l'Ecole Normale Supérieure.

These birds add to a more diverse picture of Cretaceous megafauna (big animals). Traditionally the Cretaceous, with the Jurassic and the Triassic has been referred to as the 'Age of Dinosaurs' or the 'Age of Reptiles', and the most familiar large fossils from the period have been the dinosaurs, along with the flying pterosaurs and several groups of extinct marine reptiles. In addition we have long been aware of large crocodiles and turtles from the Cretaceous. More recently palaeontologists have uncovered giant Cretaceous snakes, and Repenomamus a dog sized mammal from China, which has been found with dinosaur remains in its stomach.

See also see also The Ashdown Maniraptoran, New 'oldest bird' found in China and Birds and Dinosaurs on Sciency Thoughts Youtube.

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